package me.maxwin.view;

import android.app.Activity;
import android.content.Context;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.view.animation.DecelerateInterpolator;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.RelativeLayout;
import android.widget.Scroller;
import android.widget.TextView;

import com.netstar.salesman_90dsp.R;

public class XExpandableListView extends ExpandableListView implements
		OnScrollListener {

	private static final String TAG = "XExpandableListView";

	private float mLastY = -1; // save event y
	private Scroller mScroller; // used for scroll back
	private OnScrollListener mScrollListener; // user's scroll listener

	/** the interface to trigger refresh and load more. */
	private IXExpandableListViewListener mListViewListener;

	// -- header view
	private XExpandableListViewHeader mHeaderView;
	/**
	 * header view content, use it to calculate the Header's height. And hide it
	 * when disable pull refresh.
	 */
	private RelativeLayout mHeaderViewContent;
	private TextView mHeaderTimeView;
	private int mHeaderViewHeight; // header view's height
	private boolean mEnablePullRefresh = true;
	private boolean mPullRefreshing = false; // is refreshing.

	// -- footer view
	private XExpandableListViewFooter mFooterView;
	private boolean mEnablePullLoad;
	private boolean mPullLoading;
	private boolean mIsFooterReady = false;

	/** total list items, used to detect is at the bottom of ListView. */
	private int mTotalItemCount;

	/** for mScroller, scroll back from header or footer. */
	private int mScrollBack;
	private final static int SCROLLBACK_HEADER = 0;
	private final static int SCROLLBACK_FOOTER = 1;

	/** scroll back duration */
	private final static int SCROLL_DURATION = 400;
	/** when pull up >= 50px at bottom, trigger load more. */
	private final static int PULL_LOAD_MORE_DELTA = 50;
	/** support iOS like pull feature. */
	private final static float OFFSET_RADIO = 1.8f;
	/**
	 * default :it only can load more when the total count >=7 at last you can
	 * call the method {@link #setVisibleCount()}
	 */
	private static int VISIBLECOUNT = 7;
	private int viewHeight = 0; // the height of XExpandableListView
	private int windowHeight = 0; // the height of window
	/**
	 * default: 120px you can set the itemHeight that you need, but advice set
	 * the itemHeight 120px at last, of course you can set the itemHeight that
	 * you think the better and more modest value
	 */
	private final static int itemHeight = 120;

	/**
	 * @param context
	 */
	public XExpandableListView(Context context) {
		super(context);
		initWithContext(context);
	}

	public XExpandableListView(Context context, AttributeSet attrs) {
		super(context, attrs);
		initWithContext(context);
	}

	public XExpandableListView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		initWithContext(context);
	}

	private void initWithContext(Context context) {
		mScroller = new Scroller(context, new DecelerateInterpolator());
		/**
		 * XListView need the scroll event, and it will dispatch the event to
		 * user's listener (as a proxy).
		 */
		super.setOnScrollListener(this);

		// init header view
		mHeaderView = new XExpandableListViewHeader(context);
		mHeaderViewContent = (RelativeLayout) mHeaderView
				.findViewById(R.id.xlistview_header_content);
		mHeaderTimeView = (TextView) mHeaderView
				.findViewById(R.id.xlistview_header_time);
		addHeaderView(mHeaderView);

		// init footer view
		mFooterView = new XExpandableListViewFooter(context);

		// init header height
		mHeaderView.getViewTreeObserver().addOnGlobalLayoutListener(
				new OnGlobalLayoutListener() {
					@SuppressWarnings("deprecation")
					@Override
					public void onGlobalLayout() {
						mHeaderViewHeight = mHeaderViewContent.getHeight();
						getViewTreeObserver()
								.removeGlobalOnLayoutListener(this);
					}
				});

		DisplayMetrics metrics = new DisplayMetrics();
		((Activity) context).getWindowManager().getDefaultDisplay()
				.getMetrics(metrics);
		windowHeight = metrics.heightPixels; // 将获取的宽度存入到全局变量中
	}

	@Override
	public void setAdapter(ExpandableListAdapter adapter) {
		/**
		 * make sure XListViewFooter is the last footer view, and only add once.
		 */
		if (mIsFooterReady == false) {
			mIsFooterReady = true;
			addFooterView(mFooterView);
		}
		super.setAdapter(adapter);
	}

	/**
	 * enable or disable pull down refresh feature.
	 * 
	 * @param enable
	 */
	public void setPullRefreshEnable(boolean enable) {
		mEnablePullRefresh = enable;
		if (!mEnablePullRefresh) { // disable, hide the content
			mHeaderViewContent.setVisibility(View.INVISIBLE);
		} else {
			mHeaderViewContent.setVisibility(View.VISIBLE);
		}
	}

	/**
	 * enable or disable pull up load more feature.
	 * 
	 * @param enable
	 */
	public void setPullLoadEnable(boolean enable) {
		mEnablePullLoad = enable;
		if (!mEnablePullLoad) {
			mFooterView.hide();
			mFooterView.setOnClickListener(null);
		} else {
			mPullLoading = false;
			mFooterView.show();
			mFooterView.setState(XExpandableListViewFooter.STATE_NORMAL);
			// both "pull up" and "click" will invoke load more.
			mFooterView.setOnClickListener(new OnClickListener() {
				@Override
				public void onClick(View v) {
					startLoadMore();
				}
			});
		}
		Log.i(TAG, "mFooterView.isShown()==+++==>" + mFooterView.isShown());
	}

	/**
	 * stop refresh, reset header view.
	 */
	public void stopRefresh() {
		if (mPullRefreshing == true) {
			mPullRefreshing = false;
			resetHeaderHeight();
		}
	}

	/**
	 * stop load more, reset footer view.
	 */
	public void stopLoadMore() {
		if (mPullLoading == true) {
			mPullLoading = false;
			mFooterView.setState(XExpandableListViewFooter.STATE_NORMAL);
		}
	}

	/**
	 * set last refresh time
	 * 
	 * @param time
	 */
	public void setRefreshTime(String time) {
		mHeaderTimeView.setText(time);
	}

	private void invokeOnScrolling() {
		if (mScrollListener instanceof OnXScrollListener) {
			OnXScrollListener l = (OnXScrollListener) mScrollListener;
			l.onXScrolling(this);
		}
	}

	private void updateHeaderHeight(float delta) {
		mHeaderView.setVisiableHeight((int) delta
				+ mHeaderView.getVisiableHeight());
		/** the state is not refreshing, and then update the arrow */
		if (mEnablePullRefresh && !mPullRefreshing) {
			if (mHeaderView.getVisiableHeight() > mHeaderViewHeight) {
				mHeaderView.setState(XExpandableListViewHeader.STATE_READY);
			} else {
				mHeaderView.setState(XExpandableListViewHeader.STATE_NORMAL);
			}
		}
		setSelection(0); // scroll to top each time
	}

	/**
	 * reset header view's height.
	 */
	private void resetHeaderHeight() {
		int height = mHeaderView.getVisiableHeight();
		if (height == 0) // not visible.
			return;
		/** refreshing and header isn't shown fully. do nothing. */
		if (mPullRefreshing && height <= mHeaderViewHeight) {
			return;
		}
		/** default: scroll back to dismiss header. */
		int finalHeight = 0;
		/** is refreshing, just scroll back to show all the header. */
		if (mPullRefreshing && height > mHeaderViewHeight) {
			finalHeight = mHeaderViewHeight;
		}
		mScrollBack = SCROLLBACK_HEADER;
		mScroller.startScroll(0, height, 0, finalHeight - height,
				SCROLL_DURATION);
		// trigger computeScroll
		invalidate();
	}

	private void updateFooterHeight(float delta) {
		int height = mFooterView.getBottomMargin() + (int) delta;
		if (mEnablePullLoad && !mPullLoading) {
			if (height > PULL_LOAD_MORE_DELTA) { // height enough to invoke
													// loadmore.
				mFooterView.setState(XExpandableListViewFooter.STATE_READY);
			} else {
				mFooterView.setState(XExpandableListViewFooter.STATE_NORMAL);
			}
		}
		mFooterView.setBottomMargin(height);

		// setSelection(mTotalItemCount - 1); // scroll to bottom
	}

	private void resetFooterHeight() {
		int bottomMargin = mFooterView.getBottomMargin();
		if (bottomMargin > 0) {
			mScrollBack = SCROLLBACK_FOOTER;
			mScroller.startScroll(0, bottomMargin, 0, -bottomMargin,
					SCROLL_DURATION);
			invalidate();
		}
	}

	private void startLoadMore() {
		mPullLoading = true;
		mFooterView.setState(XExpandableListViewFooter.STATE_LOADING);
		if (mListViewListener != null) {
			mListViewListener.onLoadMore();
		}
	}

	@Override
	public boolean onTouchEvent(MotionEvent ev) {
		if (mLastY == -1) {
			mLastY = ev.getRawY();
		}
		switch (ev.getAction()) {
		case MotionEvent.ACTION_DOWN:
			mLastY = ev.getRawY();
			break;
		case MotionEvent.ACTION_MOVE:
			final float deltaY = ev.getRawY() - mLastY;
			mLastY = ev.getRawY();
			if (getFirstVisiblePosition() == 0
					&& (mHeaderView.getVisiableHeight() > 0 || deltaY > 0)) {
				/** the first item is showing, header has shown or pull down. */
				updateHeaderHeight(deltaY / OFFSET_RADIO);
				invokeOnScrolling();
			} else {
				if (VISIBLECOUNT * itemHeight > windowHeight
						&& getLastVisiblePosition() == mTotalItemCount - 1
						&& (mFooterView.getBottomMargin() > windowHeight || deltaY < -mFooterView
								.getBottomMargin() / 2)) {
					/** last item, already pulled up or want to pull up. */
					updateFooterHeight(-deltaY / OFFSET_RADIO);
				}
			}
			break;
		default:
			mLastY = -1; // reset
			if (getFirstVisiblePosition() == 0) {
				// invoke refresh
				if (mEnablePullRefresh
						&& mHeaderView.getVisiableHeight() > mHeaderViewHeight) {
					mPullRefreshing = true;
					mHeaderView
							.setState(XExpandableListViewHeader.STATE_REFRESHING);
					if (mListViewListener != null) {
						mListViewListener.onRefresh();
					}
				}
				resetHeaderHeight();
			} else if (getLastVisiblePosition() == mTotalItemCount - 1) {
				// invoke load more.
				if (mEnablePullLoad
						&& mFooterView.getBottomMargin() > PULL_LOAD_MORE_DELTA) {
					startLoadMore();
				}
				resetFooterHeight();
			}
			break;
		}
		return super.onTouchEvent(ev);
	}

	@Override
	public void computeScroll() {
		if (mScroller.computeScrollOffset()) {
			if (mScrollBack == SCROLLBACK_HEADER) {
				mHeaderView.setVisiableHeight(mScroller.getCurrY());
			} else {
				mFooterView.setBottomMargin(mScroller.getCurrY());
			}
			postInvalidate();
			invokeOnScrolling();
		}
		super.computeScroll();
	}

	@Override
	public void setOnScrollListener(OnScrollListener l) {
		mScrollListener = l;
	}

	@Override
	public void onScrollStateChanged(AbsListView view, int scrollState) {
		if (mScrollListener != null) {
			mScrollListener.onScrollStateChanged(view, scrollState);
		}
	}

	@Override
	public void onScroll(AbsListView view, int firstVisibleItem,
			int visibleItemCount, int totalItemCount) {
		// send to user's listener
		mTotalItemCount = totalItemCount;
		viewHeight = view.getHeight();
		if (mScrollListener != null) {
			mScrollListener.onScroll(view, firstVisibleItem, visibleItemCount,
					totalItemCount);
		}
	}

	public void setExpandableListViewListener(IXExpandableListViewListener l) {
		mListViewListener = l;
	}

	/**
	 * you can listen ListView.OnScrollListener or this one. it will invoke
	 * onXScrolling when header/footer scroll back.
	 */
	public interface OnXScrollListener extends OnScrollListener {
		public void onXScrolling(View view);
	}

	/**
	 * implements this interface to get refresh/load more event.
	 */
	public interface IXExpandableListViewListener {
		public void onRefresh();

		public void onLoadMore();
	}

	public void setFooterBackgroundRes(int resId) {
		if (mFooterView != null) {
			mFooterView.setBackgroundResource(resId);
		}
	}

	public void setFooterBackgroundColor(int resId) {
		if (mFooterView != null) {
			mFooterView.setBackgroundColor(resId);
			mFooterView.invalidate();
		}
	}

	/**
	 * if it is the state that is loading
	 * 
	 * @return
	 */
	public boolean isLoading() {
		return mFooterView.isLoading();
	}

	/**
	 * set a more modest visibleCount which you think
	 * 
	 * @param visibleCount
	 */
	public void setVisibleCount(int visibleCount) {
		if (visibleCount * itemHeight < windowHeight) {
			return;
		}
		VISIBLECOUNT = visibleCount;
	}

	// public void showRefresh() {
	// mPullRefreshing = true;
	// mHeaderView.setVisiableHeight(mHeaderViewHeight);
	// mHeaderView.setState(XListViewHeader.STATE_REFRESHING);
	// mListViewListener.onRefresh();
	// }
}
